This application is directed to a lamp assembly, and more particularly a high brightness lamp assembly such as a high intensity discharge (HID) light source incorporated into a parabolic reflector (PAR) housing and enclosure. The enclosure includes the housing or body, an internal surface of which is coated with a conductive reflective layer and an enlarged end of the parabolic body is closed by a lens.
Typically, the light source or bulb is inserted or mounted in the housing where an axis of the light source is substantially perpendicular to an axis of revolution of the parabolic surface. In known designs, arcing is a potential issue between the mount leads and the conductive reflective coating, particularly during hot restart applications. That is, if arcing occurs, the lamp assembly will not restart.
In the past, PAR lamps, and specifically those that incorporate high intensity discharge mount leads, have used insulators on the leads as one manner of addressing the potential arcing issue. Another possible solution is to provide a coating, such as a dichroic coating, on the reflective surface to prevent the arcing. Unfortunately, the dichroic coating requires an additional manufacturing operation and, particularly, the additional manufacturing steps are labor intensive. Consequently, the costs associated with manufacture and use of additional material increases.
It will also be appreciated that the light source in this type of lamp assembly requires a high voltage pulse (for example, on the order of 10 kV to 50 kV). The pulse is provided through one of the mount leads and thus corrective measures have been taken via insulation of the mount leads or through a protective coating with the reflective surface to limit the potential for arcing as noted above. However, a need exists for a solution that is effective, does not impact lamp performance, and preferably does not adversely impact costs.